As a lawyer and scientist for one of the world's largest makers of flame retardants, Todd Stedeford vigorously defended chemicals added to scores of household products — often by concluding the substances are far less dangerous than academic and government studies have determined.

He argued, for example, that people could be safely exposed to one flame retardant at doses more than 500 times higher than a standard set by the EPA and accused regulators of basing their decisions about toxic chemicals on emotion rather than reason.

Now Stedeford is in charge of an EPA program studying whether dozens of industrial chemicals, including flame retardants, are too dangerous. The risk assessments conducted by his office will determine whether the agency enacts more stringent regulations for certain chemicals, attempts to force some compounds off the market — or chooses to do nothing at all.

Stedeford, who worked as an EPA scientist from 2004 to 2007, rejoined the agency a year ago following a four-year stint at Albermarle, surprising some independent scientists and environmental groups.

"It's hard to imagine going from one job where you are a hired gun to another where you are supposed to be protecting the public," said Julie Herbstman, a Columbia University researcher who led a 2010 study that linked exposure to certain flame retardants with lower IQ scores in children.

EPA Administrator Lisa Jackson has publicly backed an overhaul of the way the EPA screens chemicals and urged Congress to grant the agency authority to require more testing before chemicals are allowed on the market. But the EPA is under intense pressure from the chemical industry and its congressional allies to back off.

The EPA would not make Jackson or Stedeford available for an interview. In a written response to questions from the Tribune, the agency said Stedeford has recused himself from any direct involvement in matters related to Albemarle and that steps have been taken to ensure his staff does not report to him about any work regarding flame retardants.

"The agency benefits from having employees from all sorts of backgrounds," said James O'Hara, an EPA spokesman. "Having people who are experts and are well-versed in the field is what is important."

The American Chemistry Council, the industry's chief trade group, offered similar support.

"Qualified individuals with private sector experience are assets for the federal government as they have a real-world understanding of how policy and regulatory issues can affect American businesses, the markets they serve and the consumers whose demands they meet," said Anne Kolton, a spokeswoman for the trade group. "Just as former environmental activists now serving at government agencies have a unique perspective to offer."

Some scientists said hiring Stedeford to lead the EPA's existing chemicals assessment branch exposed sharp divisions within the agency, which includes career staff who favor traditional risk assessments backed by the chemical industry and others who support newer methods.

For decades, toxicologists have tested high doses of chemicals, administering single compounds to lab animals until they get sick or die and then applying various safety factors to determine acceptable exposures for people. This method sometimes is referred to as "the dose makes the poison."

But researchers increasingly are finding that tiny doses can harm people in different ways, essentially tricking the body into responding to chemicals as hormones during key stages of development. Critics say traditional toxicology doesn't take into account the effects of these smaller amounts, or how people typically are exposed to chemicals.

Stedeford's writings at Albemarle often reflected common arguments from chemical industry lobbyists, including statements downplaying the discoveries of scores of toxic substances in the bodies of millions of Americans and letters challenging studies that documented health hazards at low doses.

In a March 2011 issue of an American Bar Association newsletter that Stedeford co-edited, he said regulators too often "accept claims from peer-reviewed articles at face value even when sufficient detail to perform a critical review is lacking."

Two months later, he co-authored a stinging response to seven scientific societies that called for "swifter and sounder" methods to test and review chemicals. The groups, representing 40,000 researchers, had written a letter to the journal Science concluding that federal laws and guidelines hamper efforts to protect Americans from hormone-disrupting chemicals.

"We do not believe that the type of public health emergency the letter posits actually exists," Stedeford and three colleagues wrote in their response. "Rather, the societies' proposal caters to the growing trend of claiming vague risks based on the mere detection of a chemical, without regard to hazard and exposure."

The real problem, they wrote, is that some researchers refuse to release raw data to their industry critics.

Stedeford and his colleagues singled out the ongoing debate about bisphenol A, an estrogen-mimicking chemical added to hard plastics and food container linings, as an example of what they called "the dangers of basing decisions on unproven techniques." Studies showing the chemical causes harm touched off "a wave of consumer panic and litigation," they wrote, referring to the widespread shunning of products thought to contain bisphenol A.

The chemical, also known as BPA, has been found in the urine of more than 90 percent of Americans. Hundreds of independent studies show that BPA can cause cancer and other diseases in animals, and the EPA has proposed listing it as a chemical that poses an "unreasonable risk" to people.

R. Thomas Zoeller, a biologist at the University of Massachusetts at Amherst who studies hormone-disrupting chemicals, said the letter co-authored by Stedeford "tried to convince people that we really don't need to look at modern science."

"It seems remarkable that anybody would go for that," said Zoeller, a leading advocate of new methods to screen chemicals for harmful effects. "We are well past the time where it is defensible to ... bring somebody into the EPA with that approach and philosophy."

Tracey Woodruff, a University of California at San Francisco researcher who studied chemicals at the EPA for 13 years, said there always is a degree of uncertainty in scientific studies. As a result, she said, EPA officials must make judgment calls at every step of the process that leads to a chemical risk assessment.

"They've made a lot of promising statements about how they are going to evaluate chemicals," said Woodruff. "But the key part of ensuring the agency makes good decisions is having senior leadership that reflects the EPA's mission to protect public health, not industry."

Before leaving to join the EPA in September 2011, Stedeford helped Albemarle in its unsuccessful fight to keep a flame retardant known as chlorinated tris, or TDCPP, off a California list of cancer-causing chemicals. Chlorinated tris was voluntarily taken out of children's pajamas in the late 1970s after it was linked to cancer, but it wasn't formally banned and since the mid-2000s has been one of the most widely used flame retardants in furniture cushions and baby products.

California's decision could lead to warning labels on products containing TDCPP. The EPA has cited industry's continued use of the chemical as a stark example of weaknesses in the federal Toxic Substances Control Act, a 1976 law that allows companies to put compounds on the market without proving they are safe and makes it practically impossible to ban them once health problems are documented.

Several major health agencies have concluded that TDCPP is a cancer risk, including the World Health Organization, National Cancer Institute and National Research Council. Stedeford and five colleagues have said there isn't enough evidence to prove the flame retardant is a human carcinogen, citing a European Union report that concluded it doesn't cause genetic damage that can lead to cancer.

Stedeford argued that another flame retardant, known as decabromodiphenyl ether, or deca, is far less harmful than the EPA and independent scientists have concluded. He kept pushing a weaker safety standard for the chemical even after Albemarle and other companies agreed in 2009 to stop making deca by 2013 in response to health concerns.

Stedeford countered that a key study the EPA relied upon was flawed. Based on his own studies, Stedeford wrote in a December 2010 letter to the EPA, people could be safely exposed daily to 571 times more deca than the agency says is acceptable.